Author(s)

Department(s)/Institutions

Introduction

The increased use of anti-TNFα antibody in Inflammatory Bowel Disease(IBD) has generated interest regarding the paradoxical triggering of psoriatic skin lesions in its users.

Aims/Background

To determine the prevalence of psoriasis in an IBD cohort with reference to clinical characteristics and anti-TNFα use.

Method

Following ethical approval,a survey questionnaire that included demographic and clinical data including age,gender,smoking status,IBD type,diagnosis of psoriasis and anti-TNFα use was posted out to all patients attending the IBD clinic in Tallaght Hospital.Incidence rates of concomitant and reactive psoriasis were analysed using a students T-test,p<0.05 was significant.

Results

In all,905 questionnaires were posted out,34%(n=312) returned,32%(n=286)were complete.In all,58% (n=166)were female,36%(n=103) and 64%(n=183) had UC and CD respectively,55%(n=157) ever smoked,44%(n=126) were ever on an anti-TNFα therapy of which 56% (n=71)had been on Adalimumab(ADA)only,18%(n=23)Infliximab(IFX) only,23%(n=29)on ADA or IFX,and 2%(n=3)were exposed to Symponi.In all,55.3%(n=57) and 54.6%(n=100) of the UC and CD cohort smoked.The overall prevalence rate of IBD and psoriasis was 9.4%(n=27),mean age 48 years(range 33-66)of which 30%(n=8)had reactive psoriasis, ie psoriasis occurring after commencement anti-TNFα therapy.The mean duration of treatment before onset of reactive psoriasis was 2.6years. The prevalence rate of psoriasis in the non-biologic and biologic cohort was 11.9%(19 of 160)and 6.3% (8 of 126) respectively, p=0.1, CI=1.82to12.57. There was a similar rate of the overall prevalence of IBD and psoriasis 9.4% (27 of 286) compared to reactive psoriasis 6.3% (8 of 126), p=0.31,CI =3.52 to 8.40 in our cohort.Interestingly,all 8 patients who had reactive psoriasis had CD and were female compared to 63%(17 of 27)CD and females in the overall psoriasis group,p=0.04, CI = 3.93to57.59. There was no association between the type of AntiTNFα prescribed with the occurrence of reactive psoriasis 6%(6 of 100) vs. 3.8%(2 of 52) ADA and IFX respectively, Odds Ratio(OR)=1.5,p=0.59, 95% CI 0.30to8.00 or smoking with any form of psoriasis in IBD,OR=1.4, p=0.42,CI= 0.6182to3.1560.

Conclusions

In our study,there was a similar prevalence rate of reactive psoriasis and background rate of psoriasis in the overall IBD cohort(6.3%vs9.4%).Our study suggests that the risk factors associated with reactive psoriasis include a diagnosis of CD and female gender. Further work to elucidate the pathophysiology of this phenomenon is required.